JPH09138944A - Nonmagnetic substrate, magnetic recording medium, magnetic recording device and roughening method of layer surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To partly build up the surface of a layer to obtain proper surface roughness by forming a partial region of a reactive material distributed by a specified density of the surface of a layer and allowing the reactive material to react with a reactive gas on the layer surface. SOLUTION: After a nonmagnetic substrate subjected to texture treatment is formed, a Cr base layer 4, a CoCrPt film recording layer 5 and a protective layer 6 are successively deposited on the substrate to form a magnetic recording medium. After a silicon oxide film 3 with such film thickness that does not form a continuous film in the plane direction is formed on the Cr film 2, the surface of the multilayered film is exposed to oxygen plasma to cause the reaction of the Cr film 2 with oxygen and partially build up the reacted part to form projections 2a on the substrate surface. In this case, by controlling the film thickness of the silicon oxide film 3 and plasma irradiation conditions, the density, diameter and height of projections 2a can be properly controlled. Therefore, the substrate surface can be easily roughened to obtain proper surface roughness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic substrate, a magnetic recording medium, a magnetic recording device, and a layer surface roughening method. More specifically, the surface of a magnetic recording medium or the like is processed to have an appropriate roughness. The present invention relates to a non-magnetic substrate, a magnetic recording medium, and a magnetic recording device on which a layer surface roughening method and a texture treatment have been performed.

[0002]

2. Description of the Related Art In recent years, in a magnetic disk device used as an external storage device of a computer, it is necessary to flatten the surface of a recording medium in order to realize high density recording. However, in a magnetic disk device adopting the contact start stop (CSS) method, adsorption occurs between the air bearing surface of the magnetic head and the surface of the magnetic recording medium at the start and stop of the operation, which hinders the running of the magnetic head. There are cases. For this reason, efforts are being made to reduce the friction between the magnetic head and the magnetic recording medium by carrying out a treatment for roughening the surface of the magnetic recording medium to a roughness that does not cause adsorption, that is, a texture treatment. Even in this case, if the height of the protrusions is made too high, spacing loss increases. Therefore, it is very important to adjust the protrusion heights in the texture processing.

For example, as shown in FIG. 8, in a magnetic disk in which an aluminum substrate 101 is coated with a NiP film 102 and a recording film 104 is formed on the aluminum substrate 101, the surface of the NiP film 102 is mechanically scored to make a magnetic field. Unevenness is formed on the disk surface. In FIG. 8, 103 is a base film and 105 is a protective film. Further, in the case of using a substrate such as glass, which is difficult to be mechanically scored, there is a technique disclosed in, for example, Japanese Patent Laid-Open No. 4-255908. As shown in FIG. 9, this technique uses a film 1 of a low surface energy metal such as Ti on a disk substrate 111.
12 is formed, and the low melting point metal film 113, for example, A
l film is formed. Further, by heat-treating the low-melting-point metal film 113, Al particles are aggregated to form protrusions uniformly distributed on the surface of the film 112, and roughening is performed. In addition, 114 is a base layer, 115 is a recording layer,
Reference numeral 116 is a protective layer. Further, there is a technique in which fine particles of Cr oxide are distributed on the surface of a substrate (magnetic tape) to form protrusions on the surface of a recording layer formed thereon.
No. 017.

Alternatively, as disclosed in Japanese Patent Laid-Open No. 5-282666, fine particles are mixed into the protective layer on the surface of the recording layer to roughen the surface of the recording medium while keeping the surface of the recording layer smooth. Is also proposed.

[0005]

However, in the conventional method for manufacturing a magnetic disk using the mechanical texture processing method shown in FIG. 8, it is difficult to control the surface shape of the magnetic disk, and there are often sharp protrusions. To do. Such protrusions may break due to contact with the magnetic head or the like to become dust, which may cause a head crash. Also,
JP-A-4-255908 or JP-A-60-26
In the method disclosed in Japanese Patent No. 1017, the number of steps in the manufacturing process increases, and the manufacturing process becomes complicated accordingly.

Further, the above three techniques roughen the underlayer of the recording layer, and as a result, the recording layer surface itself is roughened. Such surface roughness of the recording layer generally causes medium noise. On the other hand, the above-mentioned JP-A-5-282
In the method of the conventional example described in Japanese Patent No. 666, the surface of the recording medium is roughened while keeping the surface of the recording layer smooth by, for example, mixing fine particles in a protective layer on the surface of the recording layer. Therefore, roughening of the recording layer surface can be avoided, but S
There is a drawback that the device is contaminated in the process of mixing fine particles such as iO ₂ into the protective layer. That is, fine particles such as SiO ₂ are sprayed into the film forming atmosphere when the protective layer is sputtered, and these fine particles are mixed into the protective layer. As a result, the sputtering device contaminates the fine particles such as SiO _2. Therefore, maintenance of the device becomes difficult.

The present invention was created in view of the problems of the above-mentioned conventional examples, and a texture treatment method and a texture treatment capable of making the surface of a layer have an appropriate surface roughness by an easy manufacturing method. An object of the present invention is to provide a non-magnetic substrate, a magnetic recording medium, and a magnetic recording device that are subjected to the above.

[0008]

The above-mentioned problems are as follows. First, the surface of the layer in which the partial regions of the reactive material are distributed at a predetermined density within the entire surface region of the non-reactive material is exposed to the reaction gas. This is achieved by a method of roughening the surface of a layer, which comprises exposing the reactive gas to the reactive material to partially raise the surface of the layer. The step of forming a first film, the step of forming a second film made of a non-reactive material having a film thickness that does not form a continuous film on the first film, and exposing the first film to a reaction gas. A method for roughening a surface of a layer, which comprises reacting the reaction gas with the reactive material to partially swell the surface of a multilayer film including the first and second films,
First, the reactive material is chromium, and the layer surface roughening method according to the first or second aspect of the present invention is achieved. Fourth, the non-reactive material is a silicon oxide film. A fifth aspect of the present invention is achieved by the method for roughening a layer surface according to any one of the first to third aspects,
First, the step of reacting the reactive gas with the reactive material is to oxidize or nitride the reactive material by exposing it to a gas containing oxygen or nitrogen that has been turned into plasma. 4 is achieved by the method for surface roughening of a layer surface according to any one of the inventions, and 6thly, the step of reacting the reaction gas with the reactive material is performed by heating in an oxygen- or nitrogen-containing gas. It is achieved by the method for roughening a layer surface according to any one of the first to fourth inventions, characterized in that the reactive material is oxidized or nitrided. A step of forming a first film made of a reactive material, a step of forming a second film made of a non-reactive material to which a second reactive material is added, on the first film, and a reaction gas And reacting the reaction gas with the second reactive material The step of partially removing the second reactive material from the second film to expose the first film in the removal trace; and exposing the reaction gas to the reaction gas and the first film. This is achieved by a method of roughening the surface of a layer, which comprises reacting a reactive material with the surface of a multi-layered film composed of a first film and a second film to partially raise it. The reactive material is chromium, which is achieved by the method for roughening the surface of a layer according to the first or eighth invention, and ninth, the second reactive material is carbon. The non-reactive material is a silicon oxide film, which is achieved by the method for roughening the layer surface according to the first, seventh or eighth invention. Tenth, the reaction gas and the second The step of reacting with the reactive material of The second reactive material is vaporized, which is achieved by the layer surface roughening method according to any one of the first, seventh to ninth inventions, and eleventh, the above reaction. The step of reacting a gas with the first reactive material is a step of oxidizing or nitriding the first reactive material with an oxygen- or nitrogen-containing gas turned into plasma. Achieved by the method for surface roughening of a layer surface according to any one of the seventh to tenth inventions, and twelfth, the step of reacting the reaction gas with the second reactive material is an oxygen- or nitrogen-containing gas. A method for roughening a layer surface according to any one of the first, seventh to ninth inventions, characterized in that the second reactive material is vaporized by heating in an atmosphere. Thirteenth, the reaction gas and the first reaction The step of reacting with a reactive material oxidizes or nitrides the first reactive material by heating in a gas atmosphere containing oxygen or nitrogen, and the first, seventh to tenth inventions. (14) The heating method according to any one of (14) to (14), and the fourteenth, the heating is performed by laser irradiation.
The roughening of the layer surface according to any one of the first to fourteenth inventions can be achieved by the roughening method of the layer surface according to the tenth, eleventh, twelfth or thirteenth invention. Achieved by a non-magnetic substrate made by the method, the sixteenth
According to a fifteenth aspect of the present invention, there is provided a magnetic recording medium characterized in that an underlayer, a recording layer and a protective layer are sequentially laminated on a non-magnetic substrate according to the fifteenth invention.
The first film according to any one of inventions 4 to 4 is formed on the recording layer on the underlayer formed on the non-magnetic substrate, and the rough surface of the layer according to any one of the inventions 1 to 14 is formed. The present invention is achieved by a magnetic recording medium characterized by being prepared by a surface-imparting method. The eighteenth aspect is that the magnetic recording medium is a disk-shaped magnetic disk, and the rough surface of the layer surface according to the fourteenth invention is provided. A magnetic recording medium according to any one of the sixteenth to eighteenth aspects of the present invention, which is achieved by a magnetic recording medium characterized in that an inner peripheral portion and an outer peripheral portion of the magnetic disk are subjected to It is achieved by a magnetic recording device comprising:

In the present invention, the surface of the layer in which the partial regions of the reactive material are distributed at a predetermined density within the entire surface region of the non-reactive material is exposed to the reactive gas to separate the reactive gas and the reactive material. The reaction is carried out to partially raise the surface of the layer.
For example, in order to form a layer surface as described above, a first film made of a reactive material is formed, and further, a non-reactive film having a film thickness that does not form a continuous film on the first film in the planar direction is formed. A second film made of a conductive material is formed. In addition, after forming a second film made of a non-reactive material in which a second reactive material is added on a first film made of a first reactive material, the second film is exposed to a reaction gas to remove the reaction gas and the first gas. The second reactive material is reacted to partially remove the second reactive material from the second film to expose the first film in the trace of the removal.

The surface of the layer thus formed is exposed to a reaction gas so that the reaction gas reacts with the underlying reactive material. For example, when the reactive material is chromium, when oxidized or nitrided, chromium oxide or chromium nitride is formed, and the volume of that portion increases and rises to form a protrusion. At this time, when the second film having a film thickness that does not form a continuous film in the planar direction is formed, the density, diameter, and height of the protrusions can be appropriately adjusted by adjusting the film thickness. it can. In addition, when a carbon oxide-added silicon oxide film is formed, the density and size of the carbon accumulation portion can be adjusted by adjusting the carbon content. Can be adjusted to.

As described above, by using the surface roughening method of the present invention, the surface of the substrate can be easily roughened to have an appropriate surface roughness. Then, it is possible to create a magnetic recording medium that has been subjected to texture processing by this roughening method. Further, according to another magnetic recording medium of the present invention, since the roughening method is applied to the protective layer on the recording layer, roughening of the surface of the recording layer is avoided, and accordingly, the recording layer is Surface roughness can be prevented and medium noise can be suppressed.

Further, since the surface roughening method is applied to the inner and outer peripheral portions of the magnetic disk, when the magnetic disk is used in a CSS type magnetic recording device, the start of operation is particularly problematic for adsorption. Effective only when and when the operation is stopped. As a result, the texture processing can be performed only on a necessary portion, so that it is possible to reduce the medium noise due to the roughening of the recording layer.

When performing such partial texture processing, it is effective to use laser light as the heating means.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, first to fourth embodiments of the present invention will be described with reference to the drawings. (1) First Embodiment of the Invention FIGS. 1A to 1D are cross-sectional views showing a method of manufacturing a non-magnetic substrate and a magnetic recording medium according to the first embodiment.

First, as shown in FIG. 1A, a well-cleaned silicon substrate 1 having a sufficiently smooth surface is formed on the silicon substrate 1.
As shown in (b), a chromium (Cr) film (first film made of a reactive material) 2 having a film thickness of about 20 nm is formed by a DC magnetron sputtering method under the conditions of Ar gas pressure of 5 mTorr and electric power of 0.5 kW. Form. Then, as shown in FIG. 1B, Ar is formed by RF magnetron sputtering.
A silicon oxide film (second film made of a non-reactive material) 3 is formed on the silicon substrate 1 under the conditions of gas pressure of 10 mTorr and power of 0.2 kW. At this time, the silicon oxide film 3
Is set to a film thickness that does not form a continuous film in the plane direction, for example, about 3 nm.

Next, the silicon substrate 1 is placed on one of the opposing electrodes of the parallel plate type plasma processing apparatus, oxygen gas is introduced, and the gas pressure is set to 10 mTorr. Subsequently, an electric power of 600 W is applied between the opposing electrodes to turn oxygen gas into plasma, and plasma processing is performed for 10 minutes. As shown in FIG. 1 (c), the Cr film 2 partially exposed at the discontinuous portion of the silicon oxide film 3 on the surface of the substrate is oxidized by oxygen (reaction gas) turned into plasma to generate chromium oxide. It is formed. The volume of the portion increases and rises to become the protrusion 2a. In the case of the first form, as shown in FIG.
A projection 2a having a height of m and a height of 5 nm was formed.

A non-magnetic substrate that has been textured as described above is produced. Thereafter, the underlayer 4 made of a Cr film having a thickness of about 40 nm, the recording layer 5 made of a CoCrPt film having a thickness of about 20 nm, and the C film having a thickness of about 10 nm are formed on the non-magnetic substrate by a sputtering method or the like. A magnetic recording medium is produced by depositing the protective layer 6 in this order.

As described above, according to the first embodiment of the present invention, after the silicon oxide film 3 having a thickness which does not form a continuous film in the plane direction is formed on the Cr film 2, the multilayer film is formed. The surface is exposed to oxygen plasma to react oxygen with the Cr film 2,
Only the reacted portion is partially raised to form the protrusion 2a on the substrate surface. At this time, the density, diameter and height of the protrusions 2a can be appropriately adjusted by adjusting the film thickness of the silicon oxide film 3 and the plasma irradiation conditions.
The substrate surface can be easily roughened so as to have an appropriate surface roughness.

FIG. 5 shows an experimental example in which the density, diameter and height of the protrusions can be adjusted by the film thickness of the silicon oxide film 3. FIG.
The horizontal axis of is the thickness of the silicon oxide film (n
m), the vertical axis on the left shows the projection density (pieces / μm ² ) expressed on a linear scale, and the vertical axis on the right shows the projection diameter (nm) and the projection height (nm). This data was acquired under the condition that the thickness of the Cr film was 10 nm. The other conditions are the same as the above conditions.

As shown in FIG. 5, the protrusion density, the protrusion diameter, and the protrusion height show a peak-like change with respect to the film thickness of the silicon oxide film. When the film thickness of the silicon oxide film was 1 nm, the projection density, the projection height, and the projection diameter became the maximum, and 10 / μm ² , 8 nm, and 15 nm were obtained, respectively. Further, when the film thickness of the silicon oxide film is 3 nm or more, the height and diameter of the protrusions are substantially constant and do not change, but the protrusion density decreases as the film thickness increases.

The height of the protrusions 2a can be adjusted also by the processing time and the applied power. The shorter the processing time or the smaller the applied power is, the protrusions 2a.
The height of a becomes low. Further, in the first embodiment described above, the multilayer film is exposed to oxygen that has been turned into plasma to form the protrusions 2a, but heat treatment may be performed in oxygen gas. For example, under the condition of heating temperature of 400 ° C. for 30 minutes, the same protrusion density, protrusion diameter and protrusion height as described above were obtained. In this case, the height of the protrusion can be adjusted by the treatment time and the heating temperature, and the shorter the treatment time,
Alternatively, the lower the heating temperature, the lower the height of the protrusion.
For example, it was about 2 nm in the case of 10 minutes.

Further, in both the plasma treatment and the heat treatment, the same effect can be obtained by using nitrogen instead of oxygen as the treatment atmosphere. Also, the first made of a reactive material
Although the Cr film is used as the film, the present invention is not limited to this, and other materials may be used. Furthermore, although a silicon oxide film is used as the second film made of a non-reactive material, the second film is not limited to this, and another material such as a silicon nitride film, an aluminum oxide film or an aluminum nitride film may be used. Good.

(2) Second Embodiment of the Invention A method of manufacturing a non-magnetic substrate and a magnetic recording medium according to a second embodiment will be described with reference to FIGS. 2A to 2C are cross-sectional views showing a method for manufacturing a non-magnetic substrate and a magnetic recording medium. The diagram on the right is an enlarged cross-sectional view of the projection forming portion. In FIG. 1, FIG.
Items denoted by the same reference numerals as in (a) to (d) are shown in FIG.
The same thing as (d) is shown.

First, as shown in FIG. 2 (a), it was thoroughly washed.
On the silicon substrate 1 having a sufficiently smooth surface, the DC
Ar gas pressure 5 mTorr
Chromium with a film thickness of about 20 nm under conditions of r and power of 0.5 kW
(Cr) film (first film made of first reactive material) 12
To form Then, by the RF magnetron sputtering method
, Ar gas pressure 10 mTorr, power 0.2 kW conditions
And the film thickness containing carbon (C: second reactive material) is about 5
nm silicon oxide film (second non-reactive material
A film) 13 is formed. At this time, the target for spatter
As the get 21, as shown in FIG. 3, disk-shaped SiO 2
_TwoCarbon plate 23 partially attached to the surface of plate 22
Is used. Adjusting the carbon content in the silicon oxide film 13
Therefore, SiO_Two22 exposed area and carbon 23 exposed area
Adjust and. Almost the area ratio (exposed area of carbon / Si
O_TwoThe carbon content is determined in proportion to the exposed area). this
Formed by sputtering the target 21
The silicon oxide film 13a in the entire region is formed on the conoxide film 13.
On the other hand, carbon accumulated portions 13b are scattered at a predetermined density.

Next, a plasma generating power of 600 W is applied under an oxygen gas pressure of 10 mTorr, and plasma processing is performed for 10 minutes. As a result, as shown in FIG. 2B, plasma oxygen reacts with C in the carbon accumulated portion 13b, and C is vaporized and removed. The underlying Cr film 12 is exposed at the removal trace 13c. By continuing the plasma treatment,
As shown in FIG. 2C, oxygen reacts with the underlying Cr to form chromium oxide, and the volume of that portion increases and rises to form the protrusion 12a. In the case of the second embodiment, the protrusion 12a having a diameter of 100 nm and a height of 50 nm is formed.

In this way, a non-magnetic substrate is produced.
After that, the underlayer, the recording layer and the protective layer are formed through the steps similar to the step shown in FIG. 1D, and the magnetic recording medium is produced. As described above, in the second embodiment, after the C-added silicon oxide film 13 is formed on the Cr film 12, it is exposed to plasma oxygen to react oxygen with C, and the silicon oxide film 13 to C Is partially removed to remove the trace 13c.
The underlying Cr film 12 is exposed. Further, the surface of the layer is exposed to plasma oxygen to react oxygen with the underlying Cr, thereby forming chromium oxide and forming the projection 12a.

In this case, since the size and distribution density of the carbon accumulated portion 13b can be adjusted by adjusting the C content, the density, diameter and height of the protrusions 12a can be adjusted appropriately. FIG. 6 is a characteristic diagram showing the dependence of the density, diameter and height of the protrusions on the carbon composition ratio. The horizontal axis of FIG. 6 represents the carbon composition ratio (vol%) represented by the linear scale.
, And the vertical axis represents the protrusion density on a linear scale (pieces / μm
² ), protrusion height (nm) and protrusion diameter (nm). This data was acquired for a 10 nm thick chromium (Cr) film. The other conditions are the same as the above conditions.

As shown in FIG. 6, as the carbon composition ratio increases, both the projection height and the projection diameter increase. When the carbon composition ratio is about 50 vol%, the projection diameter is 100 nm, and even if the carbon composition ratio is increased from this, it hardly changes and remains almost constant. Further, the height of the protrusions becomes higher as the carbon composition ratio increases, and becomes 60 nm at about 80 vol%.
However, the dependence of the protrusion density on the carbon composition ratio is small and does not change much. It is about 1 to 2 pieces / μm ² .

The height of the protrusion 12a can be adjusted by the processing time and the applied power, and the shorter the processing time or the smaller the applied power, the protrusion 12a.
a becomes low. For example, 60 to 70 nm in 10 minutes processing time
Although it was about the same, it was rapidly lowered to about 30 nm at 9 minutes. As described above, by using the roughening method of the present invention, the substrate surface can be easily roughened so as to have an appropriate surface roughness. Then, it is possible to create a magnetic recording medium that has been subjected to texture processing by this roughening method.

If heat treatment is performed in oxygen gas at 400 ° C. for 30 minutes instead of using oxygen in plasma, the same protrusion density, protrusion diameter and protrusion height as described above can be obtained. Further, the same effect can be obtained by using nitrogen instead of oxygen in the plasma treatment and the heat treatment for forming the protrusions.

Further, although the Cr film is used as the first film made of the first reactive material, the present invention is not limited to this, and other materials may be used. Further, although the silicon oxide film is used as the second film made of the non-reactive material,
The material is not limited to this, and other materials such as a silicon nitride film, an aluminum oxide film, or an aluminum nitride film may be used.

Further, although carbon is used as the second reactive material, it is not limited to this, and other materials may be used. (3) Third Embodiment of the Invention FIGS. 4A to 4C are cross-sectional views showing a method of manufacturing a magnetic recording medium according to a third embodiment. This is an example in which the roughening method of FIG. 2 is applied to the protective layer on the recording layer 5. In the figure, the same reference numerals as those in FIG. 1 indicate the same parts as those in FIG.

First, as shown in FIG. 4A, an underlayer 4 made of a Cr film having a film thickness of about 40 nm and a film thickness of about 20 n are formed on a silicon substrate 1 having a well-cleaned and sufficiently smooth surface.
The recording layer 5 made of a CoCrPt film of m is formed in order. Subsequently, a chromium (Cr) film 12 having a film thickness of about 20 nm and a silicon oxide film 13 containing carbon having a film thickness of about 5 nm are sequentially deposited by the same method and conditions as in the second embodiment.

Next, a plasma generating power of 600 W is applied under an oxygen gas pressure of 10 mTorr to perform a plasma treatment for 10 minutes. This gives a diameter of 100 nm and a height of 50
nm projections 12a are formed. The magnetic recording medium is produced as described above. As described above, according to the third embodiment, since the protective layer on the recording layer 5 is roughened, roughening of the surface of the recording layer 5 can be avoided, and thus the surface of the recording layer 5 is roughened. Can be prevented and the medium noise can be suppressed.

(4) Fourth Embodiment of the Invention FIG. 7 is a perspective view showing a magnetic disk (magnetic recording medium) and a magnetic recording apparatus according to a fourth embodiment. Normally, the above-mentioned texture processing is applied to the entire surface of the magnetic disk.
As shown in FIG.
And that the outer peripheral portion 33 is textured. It should be noted that this figure shows a CSS type magnetic recording device.
Contact each other, and the magnetic head 34 floats above the magnetic disk 31 with a slight gap therebetween during operation.

When the above-mentioned magnetic disk 31 is used in the CSS type magnetic recording apparatus, it works effectively only at the start and stop of the operation, in which the attraction of the magnetic head 34 becomes a problem. As a result, the texture processing can be performed only on a necessary portion, so that the head flying height can be further reduced. When performing such partial texture processing, it is effective to use laser light as the heating means. It is possible to partially generate protrusions on the inner peripheral portion and the outer peripheral portion by partially heating the inner peripheral portion and the outer peripheral portion by laser irradiation in oxygen gas.

[0037]

As described above, in the present invention, the reaction is performed by exposing the surface of the layer in which the partial regions of the reactive material are distributed at a predetermined density within the entire surface region of the non-reactive material to the reaction gas. The gas reacts with the reactive material, partially raising the surface of the layer. When a second film made of a non-reactive material having a film thickness that does not form a continuous film in the planar direction is formed on the first film made of a reactive material as the layer surface, the film thickness is adjusted. By doing so, the density, diameter, and height of the protrusions formed in the discontinuous portion can be adjusted appropriately. When the second film made of the non-reactive material obtained by adding the second reactive material is formed on the first film made of the first reactive material, the second reactive material is contained. By adjusting the amount, the density and size of the accumulated portion of the second reactive material can be adjusted, so that the density, diameter and height of the protrusions formed on the traces of removal of the second reactive material can be adjusted. It can be adjusted appropriately.

As described above, according to the roughening method of the present invention, the substrate surface can be easily roughened so as to have an appropriate surface roughness. Then, it is possible to create a non-magnetic substrate or a magnetic recording medium that has been subjected to texture processing by this roughening method. Further, according to another magnetic recording medium of the present invention, since the roughening method is applied to the protective layer on the recording layer, the surface of the recording layer is prevented from being roughened and the medium noise is suppressed. You can

Further, since the above-mentioned roughening method is applied to the inner peripheral portion and the outer peripheral portion of the magnetic disk, when the magnetic disk is used in the CSS type magnetic recording apparatus, the texture processing is applied only to a necessary portion. Since it can be applied, it is possible to further reduce the flying height of the head.

[Brief description of the drawings]

1A to 1D are cross-sectional views showing a method for roughening a non-magnetic substrate and a method for producing a magnetic recording medium according to a first embodiment of the present invention.

2A to 2C are cross-sectional views showing a roughening method for a non-magnetic substrate according to a second embodiment of the present invention.

FIG. 3 is a plan view showing a structure of a sputtering target used in a method for producing a magnetic recording medium according to a second embodiment of the present invention.

4A to 4C are cross-sectional views showing a method of manufacturing a magnetic recording medium according to a third embodiment of the invention.

FIG. 5 shows the dependence of the protrusion density, the protrusion diameter, and the protrusion height on the film thickness of the silicon oxide film in the method for roughening a non-magnetic substrate according to the first embodiment of the present invention. It is a characteristic diagram.

FIG. 6 is a characteristic diagram showing the dependence of the protrusion density, the protrusion diameter, and the protrusion height on the carbon composition ratio in the roughening method for a non-magnetic substrate according to the second embodiment of the present invention. is there.

FIG. 7 is a perspective view showing a configuration of a magnetic disk and a magnetic recording device according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the structure of a magnetic recording medium that has been subjected to texture processing according to a conventional example.

FIG. 9 is a cross-sectional view showing the structure of a magnetic recording medium that has undergone texture processing according to another conventional example.

[Explanation of symbols]

1 silicon substrate, 2 Cr film (first film made of reactive material), 2a and 12a protrusions, 3 silicon oxide film (second film made of non-reactive material), 4 underlayer, 5 recording layer, 6 Protective layer, 12 Cr film (first film made of first reactive material), 13 Carbon-containing silicon oxide film (second film made of non-reactive material containing second reactive material) , 13a Silicon oxide film, 13b Carbon accumulated portion (second reactive material accumulated portion), 13c Removal trace.

Claims (19)

[Claims] 1. A surface of a layer in which partial regions of the reactive material are distributed at a predetermined density within the entire surface region of the non-reactive material is exposed to the reactive gas to separate the reactive gas and the reactive material. A method for roughening the surface of a layer, which comprises reacting to partially raise the surface of the layer. 2. A step of forming a first film made of a reactive material on a substrate, and a step made of a non-reactive material having a film thickness that does not form a continuous film on the first film in a plane direction. And a step of forming a second film, and exposing the reaction gas to the reactive material to partially raise the surface of the multilayer film including the first and second films. Method for roughening layer surface. 3. The method for roughening a layer surface according to claim 1, wherein the reactive material is chromium. 4. The method for roughening the surface of a layer according to claim 1, wherein the non-reactive material is a silicon oxide film. 5. The step of reacting the reactive gas with the reactive material is a step of oxidizing or nitriding the reactive material by exposing it to a plasma-containing gas containing oxygen or nitrogen. The method for roughening the surface of a layer according to any one of claims 1 to 4. 6. The step of reacting the reactive gas with the reactive material is to oxidize or nitride the reactive material by heating in a gas containing oxygen or nitrogen. 5. The method for roughening the layer surface according to claim 4. 7. A first reactive material is formed on a substrate.
Forming a second film made of a non-reactive material with a second reactive material added on the first film; and exposing the reaction gas to the reaction gas. Reacting with the second reactive material to partially remove the second reactive material from the second film to expose the first film at the removal trace; A method for roughening a surface of a layer, which comprises exposing the reaction gas to the first reactive material to partially raise the surface of the multilayer film including the first and second films. 8. The method for roughening a layer surface according to claim 1, wherein the first reactive material is chromium. 9. The layer surface according to claim 1, wherein the second reactive material is carbon and the non-reactive material is a silicon oxide film. Roughening method. 10. The step of reacting the reactive gas with the second reactive material is characterized in that the second reactive material is vaporized by a gas containing plasma oxygen or nitrogen. The method for roughening the layer surface according to any one of claims 1 to 7 to 9. 11. The step of reacting the reactive gas with the first reactive material comprises oxidizing or nitriding the first reactive material with a plasma-containing oxygen or nitrogen-containing gas. The method for roughening the surface of a layer according to any one of claims 1 to 7, which is characterized in that. 12. The step of reacting the reactive gas with the second reactive material vaporizes the second reactive material by heating in a gas atmosphere containing oxygen or nitrogen. The method for roughening the layer surface according to any one of claims 1 to 7 to 9. 13. The step of reacting the reactive gas with the first reactive material oxidizes or nitrides the first reactive material by heating in an atmosphere containing oxygen or nitrogen. The method for roughening a layer surface according to any one of claims 1 to 7 to 10. 14. The layer surface according to claim 5, claim 6, claim 10, claim 11, claim 12 or claim 13, wherein the heating is performed by laser irradiation. Roughening method. 15. A non-magnetic substrate prepared by the method for roughening a layer surface according to claim 1. Description: 16. A magnetic recording medium comprising a non-magnetic substrate according to claim 15 and an underlayer, a recording layer, and a protective layer, which are sequentially stacked. 17. The first film according to claim 1, wherein the first film is formed on a recording layer on an underlayer formed on a non-magnetic substrate. A magnetic recording medium produced by the method for roughening the layer surface according to any one of claims 1. 18. The magnetic recording medium is a disk-shaped magnetic disk, and the layer surface roughening method according to claim 14 is applied to an inner peripheral portion and an outer peripheral portion of the magnetic disk. Characteristic magnetic recording medium. 19. A magnetic recording apparatus comprising the magnetic recording medium according to claim 16.